Referring to FIG. 1, an assembly process of a main wing of an aircraft is explained. An upper side panel 85 in an attitude with a convex face side 85a oriented upward and a concave face side 85b oriented downward is attached to an upper side of a wing structure 87, and a lower side panel 86 in an attitude with a convex face side 86a oriented downward and a concave face side 86b oriented upward is attached to a lower side of the wing structure 87.
In an upstream process of the assembly process, the upper panel 85 is turned over such that the convex face side 85a becomes oriented upward, and the lower side panel 86 is turned over such that the convex face side 86a becomes oriented downward.
Japanese patent No. 3614612 and Japanese Patent publication (JP-A-Heisei 4-331106) disclose conventional turnover apparatuses.